LIGHT FIELD CAMERAS AND OTHER DEPTH CAMERAS

New Technology: Light Field Cameras

As we are interested in film and technology, we always try to be up-to-date concerning new developments. That way we came across the so called light field cameras, which could become interesting not only for photographers but also Filmmakers like us very soon.
These new cameras can read not only color but also depth information of a scene, which vastly increases the possibilities of post production. But light field cameras are not the only depth cameras on the market. There are others with similar functions, but a different way of functioning. In fact, you might even have one at home already: The Kinect.

Functionality of a Light Field Camera

Light field cameras generally work a little differently than usual cameras. The image sensors of normal cameras are shifted to the back to make room for an additional layer of optics. This layer is made up of an array of lenses. This way you can read not only the color information but also the direction each ray of light is originating from.
Based on this multi dimensional data, you can construct a very accurate 3D model of the scene by adding all the smaller images together. As the data is very precise, the depth information of a light field camera has a very low potential for errors.
The only difficulty and main reason why there are only a few light field cameras out there yet, is the bigger effort in manufacturing because the optics are more complex.

showcasing a lytro illum light field camera

Functionality of an Infrared Depth Camera

The Kinect and many similar depth cameras work completely different than a light field camera does: They project a fixed point pattern of the infrared spectrum onto the scene. At the same time they use an infrared camera to film it along with a traditional color camera.
Infrared projector and camera are arranged with a known distance to each other. By analysing the slight changes in the projected point pattern recorded by the infrared camera, you can mathematically work out the difference and therefore give a pretty good reconstruction of the depth of the scene. The biggest flaw of this technique is the dependence on the infrared spectrum, which means that it can not funtion properly under water or in direct sun light.

Use of Depth Cameras for Film

Depth cameras bring many advantages for film production and post production. The most advanced of them is the Lytro Cinema, which is way too expensive for the consumer market yet. For now it is only an option for productions with a very high budget, while Lytro’s light field cameras for photo have become quite affordable.

The first big advantage is the possibility of focussing after taking the shot. That does not only mean, that the production team can pay more attention to the most important things, it also means more flexibility in the post production.
Furthermore, there is no need for green screen technology anymore. Masking of any kind can now be done using the depth information, which makes the chroma green obsolete for changing for example the background of a scene.
Another benefit is the possibility of manipulating the 3D position of the camera in post. This way a simple shot on a tripod can be used to generate a clip with a bit of camera motion with correct parallax.
The last and probably biggest addition light field cameras can add to post production is the expansion of possibilities for VFX artists. One example for this would be to digitally add new light sources, which would then throw realistic shadows and influence the lighting of the real scene in a very natural way.